Ukraine has lodged a complaint against Russia at the International Court of Justice (ICJ) in The Hague to get it to halt its invasion, President Volodymyr Zelenskyy said Sunday.

"Russia must be held accountable for manipulating the notion of genocide to justify aggression," Zelenskyy declared in a tweet.

"We request an urgent decision ordering Russia to cease military activity now and expect trials to start next week."

The ICJ, which is based in the Netherlands capital The Hague, does not have a mandate to bring criminal charges against individual Russian leaders behind the four-day-old invasion.

However, it is the world's top court for resolving legal complaints between states over alleged breaches of international law. It is the supreme judicial institution of the United Nations.

The Kremlin has tried to justify its operation to "demilitarize" Ukraine as an attempt to prevent the alleged persecution of the country's Russian-speaking minority.

But the international community has roundly condemned the invasion as a flagrant breach of international law and many Ukrainian civilians have volunteered to defend their country.